I bought a NEXiLUX GC Adapter and 2 Old Skool gamecube controllers. I tried plugging in the adapter in both the front and back USB on the Wii U and tried both controllers in all slots on the adapter and nothing worked. Is the problem with my adapter or controllers? Or is it just a bad adapter/controller that I should send back in for a new one. I have been using Wiimote + nunchuck for all of smash 4 and I now that I finally got GameCube controllers, it doesn't work... someone please help me.